Authors

Abstract

Radial gas turbines are often exposed to erosion damage by particulate laden gas flows. This paper presents a numerical study of fly-ash particle trajectory and erosion through a radial turbine, based on a Lagrangian tracking code which considers particle concentration and size distribution, particle shape and fragmentation in addition to the turbulence and near wall effects as well as the stator/rotor relative positions. The obtained results indicate that the small size particles travel easily through the rotor, whereas the large ones only cross a small part around the rotor inlet and are centrifuged back. As the locations of impacts are predicted, erosion contours are evaluated and blade deterioration assessed. High erosion rates are observed over blade suction side due to high number of particles consistently impacting this small area, owing to high inward forces and direction of flow. The blade tip and exducer exhibit erosion by small particles traversing from pressure side and due to high centrifugation. The casing is eroded towards the exducer and the hub near the entry.